WHAT IS D RIBOSE? D Ribose is an organic compound that occurs naturally in every living cell. D Ribose is a building block of ATP (triphosphate), the body’s energy currency. The amino acids Tryptophan & Histidine can also be produced from converted D Ribose. D Ribose can be found in foods such as Brewer’s Yeast, but in typically modest quantities. BULK POWDERS™ D Ribose is comprised of 100% D Ribose powder. A quick check of the Certificate of Analysis (COA) on this product page